The invention relates to an automatic parking brake allowing action on a disk brake and in particular to a spring-loaded device incorporated into the piston that operates the disk brake. This spring-loaded device can be preadjusted to take account of phenomena whereby the brake disk and brake linings become cooled.
The invention therefore also relates to a method of preadjusting such an automatic parking brake.
The use of elastic components interposed in the line along which the braking forces transmitted in an automatic parking brake are transmitted in order to reduce the thermal effect is already known, for example, from documents DE 103 02 357 and EP 0 866 236. However, these systems are not compact enough and are difficult to adapt in order to be able to incorporate them into brake pistons without increasing the size of the pistons.
Furthermore, in the automatic parking brake systems incorporated into the calipers and known in the art (see U.S. Pat. No. 6,394,235 and DE 199 34 161) no braking force measurement is taken except for the measuring of the current powering the electric motor that operates the automatic parking brake actuator.
The force used to immobilize the vehicle is halted when the current powering the motor reaches a set level.
However, various factors such as temperature which may affect the correspondence between the current powering the motor and the braking force needed to immobilize the vehicle are not taken into consideration.